Reliability parameters of the Timed 25-Foot-Walk (T25FW) in patients with Multiple Sclerosis: Lower walking speed is associated with greater Smallest Detectable Change.

BACKGROUND: Reliability parameters of clinical measures should be sufficient in order to adequately monitor disease course and evaluate treatment in patients with Multiple Sclerosis (MS). The aim of this study was to assess the reliability of the Timed 25-Foot-Walk (T25FW) in patients with MS. METHODS: MS patients performed the T25FW twice with approximately one year in between. After the second measurement, they answered an anchor question using a three-point Likert scale. Taking the non-normal distribution of the T25FW into account, intraclass correlation coefficient (ICCagreement), standard error of the mean (SEMagreement) and smallest detectable change (SDC) were computed. RESULTS: 118 MS patients (76.3 % females, mean age 48.2 years) were included. Of these patients, 73 reported no change on the anchor question. They completed the T25FW at baseline in 4.7s (IQR 4.3-5.4s, n = 72) and at follow-up in 4.9s (IQR 4.3-5.9s, n = 73). The ICCagreement was 0.895, the SEMagreement was 0.037. The SDC was higher for higher mean T25FW and can be computed for each mean T25FW by 0.23*mean T25FW. CONCLUSION: Overall, in patients with MS, the T25FW has a sufficient reliability as measured with the ICC, however the SDC of the T25FW increased when patients perform worse on the T25FW (i.e. have a lower walking speed). Because this test is often used in MS patients with limited walking ability, these findings are important to keep in mind when interpreting the re-test scores of the T25FW.

Reliability of IMU-Based Gait Assessment in Clinical Stroke Rehabilitation.

BACKGROUND: Gait is often impaired in people after stroke, restricting personal independence and affecting quality of life. During stroke rehabilitation, walking capacity is conventionally assessed by measuring walking distance and speed. Gait features, such as asymmetry and variability, are not routinely determined, but may provide more specific insights into the patient's walking capacity. Inertial measurement units offer a feasible and promising tool to determine these gait features. OBJECTIVE: We examined the test-retest reliability of inertial measurement units-based gait features measured in a two-minute walking assessment in people after stroke and while in clinical rehabilitation. METHOD: Thirty-one people after stroke performed two assessments with a test-retest interval of 24 h. Each assessment consisted of a two-minute walking test on a 14-m walking path. Participants were equipped with three inertial measurement units, placed at both feet and at the low back. In total, 166 gait features were calculated for each assessment, consisting of spatio-temporal (56), frequency (26), complexity (63), and asymmetry (14) features. The reliability was determined using the intraclass correlation coefficient. Additionally, the minimal detectable change and the relative minimal detectable change were computed. RESULTS: Overall, 107 gait features had good-excellent reliability, consisting of 50 spatio-temporal, 8 frequency, 36 complexity, and 13 symmetry features. The relative minimal detectable change of these features ranged between 0.5 and 1.5 standard deviations. CONCLUSION: Gait can reliably be assessed in people after stroke in clinical stroke rehabilitation using three inertial measurement units.

Determining the minimal important change of the 6-minute walking test in Multiple Sclerosis patients using a predictive modelling anchor-based method.

BACKGROUND: The minimal important change (MIC) of the 6-minute walk test (6MWT) is not clear for patients with Multiple Sclerosis (MS), hampering treatment evaluation. The aim of our study was therefore to determine the MIC of the 6MWT in MS patients. METHODS: MS patients did the 6MWT using the instruction to walk at comfortable speed twice with approximately one year in between. After the second 6MWT they completed 3-point anchor question. The MICadjusted with a 95% confidence interval (CI) was calculated with the predictive modelling method with bootstrapping. RESULTS: 118 MS patients (mean age 48.2 years, 23.7% men) were included between September 2018 and October 2019. Mean 6MWT distance was 468 ± 112 m at baseline and 469 ± 115 m one year later. Twenty-three (19.5%) patients answered their walking distance improved, 43 (36.4%) answered it worsened. A MICadjusted for improvement of 19.7 m (95%CI 9.8-30.9 m) was found, and for deterioration of 7.2 m (95%CI -3.3-18.2 m). CONCLUSIONS: Using the most sophisticated statistical method, the MICadjusted of the 6MWT in MS patients was 19.7 m for improvement, and 7.2 m for deterioration. This knowledge allows physiotherapists and physicians to evaluate if their treatment has led to a meaningful improvement for their MS patients or if walking of their patients has deteriorated.